Hail Demo: Terminal Velocity
The only thing that rivals the challenge of making realistic hailstones is developing a system for delivering them in a way that simulates the type of terminal velocity achieved in nature. On February 20, approximately 10,000 hailstones will take flight from a catwalk some 60 ft. high inside the IBHS Research Center.
IBHS researchers will activate 72 barrels on a dozen hail cannons mounted on the catwalk to simultaneously to fire an array of hailstones in a national media event to be televised by NBC’s Today Show, The Weather Channel and more than 20 other media outlets. Media coverage begins at 7 a.m. EST on Today.
The custom-made compressive air cannons are outfitted with sleeves that use a gravity feed hopper system. Researchers can shoot three sizes of hailstones in different directions in 3-second intervals to simulate an actual hailstorm.
Innovative in Action: Launching Hail
After investigating numerous options, IBHS researchers determined there was no off-the-shelf solution for launching hailstones. So, the engineers designed and built multi-barreled hail cannons, which they mounted on the Research Center catwalk, 60 feet above the test specimen house inside the center’s massive test chamber.
“Creating hailstones and designing and building the hail cannons were two of the greatest challenges we faced,” says lead hail research Dr. Tanya Brown. “But, like every research project we undertake at IBHS, getting the science right is paramount. We thoroughly investigated many hailstone formulas and hailstone delivery prototypes to ensure our hailstorm capabilities provide the closest match possible to Mother Nature.”
During the full-scale IBHS hailstorm, multi-barreled hail cannons will launch hailstones ranging from diameters of 1 in., 1.5 in. and 2 in. at up to 76 mph. The cannons are aimed a 20 ft. by 20 ft. residential-style test specimen featuring different types of roofing and siding materials. In the first-ever demonstration of this capability, to simulate a common residential space, IBHS will place a car and typical outdoor furniture, toys, and accessories near the structure.
IBHS Hailstorm Demonstration – Developing the Cannons
Developing a cannon’s loading mechanism.
A hail cannon being tested at the IBHS Research Center.
Early tests of a hail cannon at the IBHS Research Center.
A hail cannon mounted on the catwalk at the IBHS Research Center.
Dr. Ian Giammanco, IBHS research scientist, works on a hail cannon.
Hail cannons are shown being installed on the catwalk at the IBHS Research Center.
© 2012 Insurance Institute for Business & Home Safety